Q: 2 siuations: #1 Engine stutters at 3k rpm. #2 Car can barely accelerate and stutters when it does. VSA + Checkengine light flashin

Depending on how my car is feeling when I turn it on, two scenarios occur:

Scenario 1) Car turns on, check engine light is on. Car feels totally fine and I accelerate fine, until it hits 3k RPM. Once it hits that, the engine starts stuttering and it can't accelerate past the 3krpm. As long as i let go of the gas (which drops the rpm) it's fine.

Scenario 2) Turn the car on & check engine light is on and flashing. The VSA light is on and a triangle with a ! is on too. In this scenario, I cannot accelerate at all without the engine stuttering. When the car does the natural coasting of being in drive, it doesn't stutter, but the second I touch the gas pedal, instant stuttering and it can't do anything.

A friend of mine changed the crank shaft sensor and disconnected the battery for an hour and the car had been working for 2 weeks after that. But now I'm having the same issues again.

Check Engine codes: Cylinder misfire 1 & 2 and something about emissions. It changes based on scenario.

My car has 70000 miles.
My car has an automatic transmission.